Current transformer



Jan. 5, 1937.

F. J. FISCHER CURRENT TRANSFORMER Filed June 10, 1953 1/ 12 20 22 27 Y E aw p, 275 I 27f I ;9 E 23 2 Sheets-Sheet 1 a -IlE [1MP III, I 110.

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Manda kw A TTORNEYS Jan. 5, 1937. J 5c 2,066,396

CURRENT TRANSFORMER Filed June 10, 1933 2 Sheets-Sheet 2 11v VENTOR fiiea/vz J, P750452 BY Wink 9&4;

ATTORNEXS Patented Jan. 5, 1937 UNITED STATES PATENT OFFICE CURRENT TRANSFORMER Franz Joseph Fischer, Dresden-Mickten, Germany, assignor to Koch & Sterzel Aktiengesellschaft, Dresden, Germany Application June 10, 1933, Serial No. 675,205 In Germany June 10, 1932 4 Claims. (Cl. 175-358) This invention relates to current transformers may be placed conveniently upon the insulating and refers more particularly to so-called spreader body 2|. current transformers provided with a pot-shaped The insulating bodies 20 and 2! are hollow. A insulating body. rectangular tube i2 is situated within the inteil Current transformers known in prior art are rior of the hollow insulating body 20 and con- 5 comparatively high and bulky in size. In order stitutes an integral part of that body. The inteto eliminate this drawback it has been proposed rior of the tube I2 is designated by the numeral to construct transformers comprising two or more i3 in the drawings. insulating bodies which are arranged side by side The hollow insulating body H is provided with in stepped formation. This construction howa similar tube It, which is situated within the in ever was found to be unsatisfactory. insulating body 2| and forms an integral part of An object of this invention is the provision of this body. Theinterior of the tube I8 is desigcurrent transformers which have a comparatively nated by the numeral I 1 in the drawings. low height and which at the same time are in- As shown in Figure 1a, the adjacent portions of 18 expensive and convenient to manufacture and the insulating bodies 20 and H have the shape of are eflicient in operation. The above and other steps which are adapted to be placed one over objects of the present invention may be realized the other in such manner that the surface 22 of through the provision of current transformers the insulating body is situated over the tube which comprise a plurality of super-imposed in- IS, constituting a part of the body 2 i. When the 20 sulating bodies, said insulating bodies having insulating body 20 is placed over the insulating portions which are situated side by side when the body 2! in this manner, the surface 23 of the transformers are assembled. insulating body if is situated underneath the The invention will appear more clearly from tube i2 of the insulating body 28. This position the following detailed description when taken in is shown in Figure 1 of the drawings. In this po 25 connection with the accompanying drawings sition, the passages l1 and i3 of the two insulat- 25 showing by way of example preferred embodiing bodies are in alignment with each other, ments of the inventive idea. forming asingle continuous passage having a In the drawings: common central axis. In this assembled position, Figure 1 is a section through a portion of a the tubes i8 and I! are situated opposite each transformer constructed in accordance with the other and each one of them forms a continua- 3o principles of the present invention, and illustion of th other, trates diagrammatically the adjacent portions of The tube I: of the insulating body 20 serves two insulating bodies of the transformer and the as a, support for the primary winding II which windings carried by these portions. is wound in coils around the tube l2 as shown in Figure la showsin perspective the two insulat- Figure l. The terminals Ila and lib of the 35 ing bodies which, when assembled, constitute the primary winding H may be connected to any suitbody of the transformer shown in Figure 1. able source of electrical energy not shown in the Figures 2, 3 and 4 are vertical sections through drawings. differently constructed transformers. The tube l8 of the insulating body 2| serves Figures 5 illustrates a transformer provided as a carrier for the secondary winding I 9 which 40 with means for increasing the stability thereof. is wound around the tube i8.

Figure 6 is a section along the line 6-6 of Fig- In the example illustrated in the drawings, the w 5, two ends of the secondary winding l9 are con- Figure 7 shows a transformer of a somewhat nected to a measuring instrument Ilia. different construction. An iron core i4 is situated within the passages 45 Figure 8 illustrates diagrammatically a trans- I1 and I3 formed by the aligned tubes l8 and I2. former provided with a switch. Any suitable means not shown in the drawings The transformer illustrated in Figures 1 and may be used for supporting the iron core H with- 1a of the drawings comprises two separate holin the passages I1 and Hi. In actual practice the low insulating bodies 20 and 2!. In Figure 1, core I4 fills out the passages practically en 50 the insulating body 20 is shown as being placed tirely. on top of the insulating body 2|. In Figure 1a The core I carriesawinding l5 which is wound the two insulating bodies are shown in perspecpractically around the entire core. As shown in tive separately from each other, but it is illus- Figure 1, the two ends of the coil i5 are joined trated in that figure that the insulating body 20 together so that this coil constitutes an entirely 55 separate closed electrical circuit. The only current passing through the coil I! is that induced by the electric and magnetic field produced by the coil II. The purpose of the coil Il is to transmit power from the primary winding to the secondary winding and to diminish losses of the transformer.

The insulating body I is provided with a flange I6 surrounding the entire body and formed a little above the surface II of the insulating body Ill.

The insulating body II is provided with a similar flange 21, which surrounds the entire insulating body II and which is situated somewhat below the surface I! of the insulating body II. Metallic sheets 21 are diagrammatically designated by broken lines in Figure l and are firmly connected to the adjacent surfaces of the insulating bodies II) and II which carry these metallic sheets. The metallic sheets I1! are electrically connected with the iron core II as indicated by the reference character 21b in Figure 1.

Since the tube II is situated within the hollow insulating body 20, the primary winding I I carried by the tube II is also situated within the body 20.

The secondary winding is is situated within the insulating body II since it is carried by the tube III which is situated within that insulating body.

Due to the described arrangement, a two-stage current transformer is formed which has the form of a compact column and which is very firm and stable in construction, although it occupies a comparatively small space.

The transformer illustrated in Figure 2 of the drawings comprises insulating bodies which are substantially similar to the insulating bodies shown in Figure 1. The characteristic feature of the transformer shown in Figure 1 is that it is formed by two insulating bodies placed one on top of the other. The characteristic feature of the transformer shown in Figure 2 is that it is formed by two insulating bodies, the adjacent walls of which have been united by baking or a similar process. Due to this baking, the transformer shown in Figure 2 comprises a single insulating body having an upper hollow portion Ila, the outer surface of which is provided with an annular flange Ila. The lower portion of the hollow insulating body is designated by the reference character Ila in Figure 2, and is provided with an annular flange Ila.

The interior of the hollow insulating body shown in Figure 2 is provided with several partition walls. A flat partition wall 22a is firmly attached to the upper portion Illa of the insulatlng body and is connected by a ridge ll with two parallel flat partition walls 5i and SI. A hollow tube Ila is also situated within the insulating body and has one end which is flrmly joined to the portions a and Ila of the insulating body. The opposite end of the tube Ila is flrmly connected with the partition wall 5| and with another partition wail lla, which is situated directly underneath the partition wall II.

Another tube IIa is also situated withinthe hollow insulating body and constitutes a continuation of the tube Ila. One end of the tube IIa is firmly connected to the portions Illa and Ila of the insulating body while the other end of the tube IIa is connected to the partition wall 52 and to another partition wall lIa which is joined by the ridge a to the partition wall 5Ia. Another flat partition wall Ila is joined to the portion Ila and to the wall Ila of the insulating body.

The primary winding Ila of the transformer is wound around the inner tube I241. The secondary winding Ila of the transformer is wound around the tube Ila. An iron core Ila is situated within the tubes Ila and i211. The iron core Ila carries a winding Ila which is entirely separate from all other windings and the two ends of which are connected with each other. Ibis transformer operates in substantially the same manner as that illustrated in Figure l.

The transformer shown in Figure 3 comprises an upper insulating body Ilb which is similar in form to the insulating body 2' shown in Figure l.

The insulating body II is hollow and is provided with an upwardly extending hollow portion ll containing a single tube lI which extends horizontally across the entire transformer. The tube II has a laterally extending portion forming a tube lI which is concentric with respect to the tube H and encloses a portion thereof. The insulating body Ilb has a downwardly extending hollow portion ll provided with a hollow tube ll fitting over the tube ll of the body ll. The tube ll is concentric in relation to the tube II when the transformer is assembled.

The tube ll serves as a carrier for the secondary winding Ilb which is wound around the tube ll and the ends or which are shown in the drawings as being connected to a measuring instrument.

The primary winding III) is wound in coils which are wound around the tube ll. Due to this arrangement, the primary winding III) is concentrical in relation to the major portion of the secondary winding Ilb. The transformer losses are considerably diminished due to this construction.

The transformer illustrated in Figure 4 comprises an insulating body II which is adapted to be placed over the insulating body II. The. insulating body I! comprises a horizontal par-' tition wall 30 which, when the transformer is assembled, is situated above the partition wall ll forming a part of the insulating body 31. Another horizontal partition wall II is situated in the same plane as the partition wall ll and is attached to the opposite side of the insulating body as. A third partition wall 33 of the insulating body 29 is situated much higher than the partition walls ll and II, and is connected by vertical side walls 34 and II with them. A tube ll is situated within the insulating body II and is connected to the partition wall ll and to an outer wall of the insulating body Il.

Another tube ll is also situated within the insulating body I9 and is substantially in alignment with the tube ll. The ends of the tube ll are connected to the opposite outer wall of the insulating body I! and to the partition wall 35.

The lower insulating body 31 comprises vertical site the wall ll while the wall I is situated I opposite the wall II. A tube ll is situated within the lower insulating body ll and its ends are connected with the vertical side walls ll and ll respectively. The tube ll is in alignment with the tubes ll and ll so that all these tubes havea common central axis.

The primary winding of the transformer shown in Figure 4 consists of two coils IIc and Hit which are connected in series by the wire He. The coil He is wound around the tube 36 while the coil IId is wound around the tube 90.

The secondary winding of the transformer is formed by the coil I90 which is wound around the tube 43 of the lower insulating body 01.

The transformer illustrated in Figures 5 and 6 of the drawings comprises an insulating body III which is hollow and which carries an inner rectangular tube II. The lower end of the insulating body I is formed by parallel horizontal partition walls I2 and I3 which are interconnected by the vertical partition wall I4. The tube II carries the primary winding I5 which Is wound around the tube II.

The lower insulating body I6 which carries the upper insulating body I0, comprises an inner tube I1 which is in alignment with the tube 'II. The tube II carries the secondary winding I0 of the transformer.

An iron core I9 is situated within the tubes I1 and II and is supported therein by any suitable means not shown in the drawings. The iron core 19 carries two coils 00 and M which are wound side by side upon the core I9 and the ends of which are connected in parallel with each other.

A bottle-like insulating body 02 is placed upon the upper insulating body 10 and serves as a closure for the insulating body 10. A conical hollow body 83 is situated within the interior of the lower insulating body I6 and is used for increasing the stability of the transformer. Sand 84 fills the interiors of the insulating bodies 82, 10 and 16.

As shown in Figure 5, the primary winding is connected by wires 85 and 06 to a winding 875' which is wound around an iron core 88. Another separate winding 89 is wound concentrically around the winding 8! and its two ends are connected by wires 90 and ill to terminals 92 and 93 respectively. Due to this arrangement, a twcstage transformer is formed which is comparatively low in height and very eilicient in operation. It will be noted that in the transformer shown in Figure 5, there are two sets of windings which are inductively coupled, thereby forming a two-stage transformer; namely, the winding 89 is inductively coupled with the winding 01 and the winding I5 is inductively coupled with the winding I8.

The transformer illustrated in Figure 7 of the drawings comprises an upper insulating body I00 which is provided with a tube IOI, which is adapted to be placed on top of the lower insulating body I02 provided with a tube I03 which is in alignment with the tube IN. A third insulating body I04 is placed on top of the insulating body I00 and is provided with an inner tube I05.

The tube IOI carries the primary winding I06 which is connected by wires I01 and I00 with the winding I09 carried by the tube I05. An iron core H0 is situated within the tube I05 and carries a winding III, the two ends of which are connected to terminals H2 and H3 adapted to be connected to any suitable source of electrical energy. The tube I03 carries the secondary winding II4 which is wound around the tube I03.

In operation, the terminals H2 and H3 are joined to the source of electrical energy, so that an alternating current passes through the winding III. This alternating current induces an alternating current in the winding I09 which surrounds the winding III and is entirely separate therefrom. The current induced in the winding I09 is transmitted by the wires I01 and I08 to the winding I06. The winding I06, through the medium of the separate short-circuited winding II5 induces an electrical current in the secondary winding II4.

The transformer shown in Figure 8 of the drawings comprises an upper insulating body I I1 provided with a tube I I8 and adapted to be placed upon the lower insulating body II 9 which carries the tube I20. A cylindrical top portion I2I is placed upon the insulating body I IT.

The tube IIO carries the primary winding I22 while the tube I carries the secondary winding I23. Wires I24 and I25 are connected to the two ends of the primary winding I22. The wire I24 is connected to one of the terminals of a source of electrical energy. The wire I25 is connected to a switch I26 which is connected to the other terminal of the same source. The switch I26 is used for interrupting the connection between the primary winding I22 and the source of electrical energy which is not shown in the drawings.

I claim:-

1. In a current transformer, a lower insulating body, an upper insulating body carried by said lower insulating body, an insulating tube carried by said lower insulating body, an insulating tube carried by said upper insulating body, said insulating tubes being situated end to end and in alignment in relation to each other, one of said tubes forming a continuation of the other tube, the common central axis of said tubes being substantially transverse to the axis of said insulating bodies, a primary winding carried by one of said tubes, and a secondary winding carried by the other one of said tubes.

2. In a current transformer, a lower insulating body having a projecting portion, an upper insulating body carried by said lower insulating body and having a projecting portion fitting adjacent the first-mentioned projecting portion, an insulating tube carried by the first-mentioned projecting portion, another insulating tube carried by the second-mentioned projecting portion, said insulating tubes having the same diameter and being situated end to end and in alignment in relation to each other, one of said tubes forming a continuation of the other tube, the common central axis of said tubes being substantially transverse to the axis of said insulating bodies, a primary winding carried by one of said tubes, and a secondary winding carried by the other one of said tubes, and an iron core situated within said tubes.

3. In a current transformer, a lower insulating body having a projecting portion, an upper insulating body carried by said lower insulating body and having a projecting portion fitting adjacent the first-mentioned projecting portion, an insulating tube carried by the first-mentioned projecting portion, another insulating tube carried by the second-mentioned projecting portion, said insulating tubes having the same diameter and being situated end to end and in alignment in relation to each other, one of said tubes forming a continuation of the other tube, the common central axis of said tubes being substantially transverse to the axis of said insulating bodies, a primary winding carried by one of said tubes, a secondary winding carried by the other one of said tubes, and insulating partition walls interconnecting said tubes.

4. In a current transformer, two insulating bodies, one of said insulating bodies being carried by the other insulating body, one of said insulating bodies having two projecting portions, the other one of said insulating bodies having a projecting portion fitting between the two firstmentioned projecting portions, insulating tubes carried by said projecting portions, said insulating tubes having the same diameter and being situated end to end and in alignment in relation to each other, one of said tubes forming a cou- 

